CVE-2025-21599

HIGH
Published Jan 9, 2025 Modified Jan 26, 2026 CWE-401

Description

A Missing Release of Memory after Effective Lifetime vulnerability in the Juniper Tunnel Driver (jtd) of Juniper Networks Junos OS Evolved allows an unauthenticated network-based attacker to cause Denial of Service.  Receipt of specifically malformed IPv6 packets, destined to the device, causes kernel memory to not be freed, resulting in memory exhaustion leading to a system crash and Denial of Service (DoS). Continuous receipt and processing of these packets will continue to exhaust kernel memory, creating a sustained Denial of Service (DoS) condition. This issue only affects systems configured with IPv6. This issue affects Junos OS Evolved:  * from 22.4-EVO before 22.4R3-S5-EVO,  * from 23.2-EVO before 23.2R2-S2-EVO,  * from 23.4-EVO before 23.4R2-S2-EVO,  * from 24.2-EVO before 24.2R1-S2-EVO, 24.2R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 22.4R1-EVO.

Is your site exposed to CVE-2025-21599?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.5
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-401 CWE-401

Affected Products

Vendor Product
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved

References

Frequently Asked Questions

What is CVE-2025-21599? +
A Missing Release of Memory after Effective Lifetime vulnerability in the Juniper Tunnel Driver (jtd) of Juniper Networks Junos OS Evolved allows an unauthenticated network-based attacker to cause Denial of Service.  Receipt of specifically malformed IPv6 packets, destined to the device, causes kernel memory to not be freed, resulting in memory exhaustion leading to a system crash and Denial of Service (DoS). Continuous receipt and processing of these packets will continue to exhaust kernel memory, creating a sustained Denial of Service (DoS) condition. This issue only affects systems configured with IPv6. This issue affects Junos OS Evolved:  * from 22.4-EVO before 22.4R3-S5-EVO,  * from 23.2-EVO before 23.2R2-S2-EVO,  * from 23.4-EVO before 23.4R2-S2-EVO,  * from 24.2-EVO before 24.2R1-S2-EVO, 24.2R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 22.4R1-EVO. It has a CVSS v3.1 base score of 7.5 (HIGH).
How severe is CVE-2025-21599? +
CVE-2025-21599 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
What products are affected by CVE-2025-21599? +
CVE-2025-21599 affects products from juniper, specifically: junos_os_evolved. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2025-21599? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2025-21599 — free, no signup required.